Electron Beam Patterning System In Additive Manufacturing

ABSTRACT

A method and an apparatus involve applying a pattern on an addressable patternable cathode unit. The cathode unit is stimulated to emit an electron beam pattern. A patterned image in the electron beam pattern is positioned to a desired position such directly to as a powder bed for additive manufacturing or to an electron beam addressed light valve for controlling spatial patterns on an optical signal for powder bed manufacturing.

CROSS REFERENCE TO RELATED PATENT APPLICATION

The present disclosure is part of a continuation-in-part (CIP) of U.S.patent application Ser. No. 15/337,507, filed on Oct. 28, 2016 andclaiming the priority benefit of the following provisional applications:

U.S. Patent Application No. 62/248,758, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,765, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,770, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,776, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,783, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,791, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,799, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,966, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,968, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,969, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,980, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,989, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,780, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,787, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,795, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,821, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,829, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,833, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,835, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,839, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,841, filed on Oct. 30, 2015,

U.S. Patent Application No. 62/248,847, filed on Oct. 30, 2015, and

U.S. Patent Application No. 62/248,848, filed on Oct. 30, 2015, whichare incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure generally relates to optics and, morespecifically, to polarization combining in additive manufacturingsystems.

BACKGROUND

The ability to deliver high intensity laser light to the build platformis a requirement for additively manufacturing objects using laser-basedtechniques in the powder bed fusion method. The exact laser intensity(energy per unit area) is material dependent and is based on the thermaldiffusivity of the substance (the ratio of thermal conductivity tovolumetric specific heat) as well as the melt temperature of thematerial and heat of fusion. Higher thermal diffusivity and higher melttemperatures mean that the material to be melted requires higher laserintensity.

To date, optical systems for semiconductor (e.g. diode) laser-basedadditive manufacturing with the highest time averaged intensitysemiconductor lasers commercially available having the potential toachieve intensities of 117 kW/cm{circumflex over ( )}2 while meeting anoptical resolution requirement of 7 um point imaging full width halfmaximum (FWHM). Commercial solid state (e.g. fiber) based laser systemsare able to focus their beam to very high intensities with ease due tothe high beam quality and coherence. Experiments have shown thatintensities greater than 370 kW/cm{circumflex over ( )}2 are sufficientto generate fully dense stainless steel parts using the laser powder bedfusion method. Intensities lower than this will potentially not bond themelted powder to the base before surface tension pulls it into a ball.It is thus a requirement to avoid this effect for additivelymanufacturing materials using the laser based powder bed fusion method.

Semiconductor lasers are typically cheaper than solid state lasersystems commonly used in powder bed fusion additive manufacturingsystems. While semiconductor lasers are cheaper, they suffer inbrightness. Currently, solid state laser systems are capable ofachieving feature sizes of ˜100 um, while also maintaining a largedistance greater than 250 mm between the final build platform and thepowder distribution mechanism to allow new layers of powder to bedeposited. To achieve the same resolution on the powder bed of suitablelength with semiconductor lasers, high brightness is a requirement.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present disclosureare described with reference to the following figures, wherein likereference numerals refer to like parts throughout the various figuresunless otherwise specified.

FIG. 1A illustrates an additive manufacturing system;

FIG. 1B is a top view of a structure being formed on an additivemanufacturing system;

FIG. 2 illustrates an additive manufacturing method;

FIG. 3A is a cartoon illustrating an additive manufacturing systemincluding lasers;

FIG. 3B is a detailed description of the light patterning unit shown inFIG. 3A;

FIG. 3C is one embodiment of an additive manufacturing system with a“switchyard” for directing and repatterning light using multiple imagerelays;

FIG. 3D illustrates a simple mirror image pixel remapping;

FIG. 3E illustrates a series of image transforming image relays forpixel remapping;

FIG. 3F illustrates an patternable electron energy beam additivemanufacturing system;

FIG. 3G illustrates a detailed description of the electron beampatterning unit shown in FIG. 3;

FIG. 3H illustrates an example of a high-speed electron beam addressedRLV (EBA-RLV)

FIG. 3I illustrates an example of an Embodiment to an EBA-RLV using anelectronically addressable EBA array (e-EBA-RLV)

FIG. 3J illustrates an example of an Embodiment to an EBA-RLV using anoptically addressed EBA (o-EBA-RLV).

FIG. 3K illustrates an example of an Embodiment to an electron beampatterning unit using an optically addressed electron beam printingengine

FIG. 3L illustrates an example of an embodiment to an optically electronprinting head with an electrically addressed 2D scanner

FIG. 3M illustrates an example of an embodiment of an opticallyaddressed electron beam print head scanner

FIG. 4 is a diagram illustrating an example optical assembly ofpolarization combining to achieve up to two times the originalsemiconductor laser intensity in accordance with an embodiment of thepresent disclosure;

FIG. 5 is a diagram illustrating an example optical assembly ofpolarization combining to achieve up to 100% system transmission of theoriginal semiconductor laser intensity in accordance with an embodimentof the present disclosure;

FIG. 6 is a flowchart of an example process in accordance with thepresent disclosure; and

FIG. 7 is a flowchart of another example process in accordance with thepresent disclosure.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanyingdrawings that form a part thereof, and in which is shown by way ofillustrating specific exemplary embodiments in which the disclosure maybe practiced. These embodiments are described in sufficient detail toenable those skilled in the art to practice the concepts disclosedherein, and it is to be understood that modifications to the variousdisclosed embodiments may be made, and other embodiments may beutilized, without departing from the scope of the present disclosure.The following detailed description is, therefore, not to be taken in alimiting sense.

The present disclosure proposes an optical system suitable forhigh-resolution imaging of high average power light sources independentof wavelength, thus allowing the combination of polarization states toincrease laser intensity and/or reduce system power losses. Accordingly,the proposed optical system may be suitable for use in semiconductorlaser-based additive manufacturing. Using polarization combining opticalgeometries enables up to 2× increase in output intensity, near 100%transmission efficiency, or both. Increases in semiconductor laserintensity allow for the processing of wider ranges of.

The disclosed optical system is capable of increasing the intensityand/or efficiency of semiconductor laser light through polarizationcombination. Semiconductor lasers are typically polarized to about70-90% in one polarization state. When using a polarization rotatingmethod to pattern the light, the 10-20% of the light in the undesiredpolarization state could potentially go unused (rejected). To avoid thisloss, polarization combining and patterning can be used to either boosttransmission efficiency or increase resultant intensity by a factor of2, or both.

One example of semiconductor lasers and polarization states is to usehighly polarized semiconductor lasers, with half of the lasers orientedin one polarization state, and half in the other. The minoritypolarization state of the two polarization states in each half of thesemiconductor lasers is rejected, with the majority polarization statepassed through a spatial light modulator (such as an optically addressedlight valve) corresponding to the respective polarization state of thelight. Each light valve applies a polarization pattern to the laserlight, and each of the two light valves may have different or the sameapplied pattern. The two different polarization states are then combinedto achieve two times (2×) the initial intensity while maintaining thedesired polarization state pattern. In some embodiments, the twopolarization states may be patterned by any mask or other light blockingmechanism and then re-combined because of their different polarizationstates. In some embodiments, the two polarization states may be firstcombined because of their different polarization states and thenpatterned by any mask or other light blocking mechanism.

A second example of lasers and polarization states is to use more thanone laser of an arbitrary polarization state. A polarizer is used tosplit the beam(s) into its (their) respective polarization state(s), andspatially stack the beam(s) of corresponding polarization state(s) closetogether by spatial positioning creating two effective beams, with oneof each polarization state. These two beams, of different polarizationstate, are then passed through a light modulator relating to theirperspective polarization state, then with a polarization state patternapplied in the beam, and subsequently beam combined by polarizationcombining. This method uses all light in the process, which allows forhigher usage of the laser light, thereby achieving minimal to no losses,due to variance in polarization state, as well as better systemefficiency.

As seen in FIG. 1, an additive manufacturing system 100 has an energypatterning system 110 with an energy source 112 that can direct one ormore continuous or intermittent energy beam(s) toward beam shapingoptics 114. After shaping, if necessary, the beam is patterned by anenergy patterning unit 116, with generally some energy being directed toa rejected energy handling unit 118. Patterned energy is relayed byimage relay 120 toward an article processing unit 140, typically as atwo-dimensional image 122 focused near a bed 146. The bed 146 (withoptional walls 148) can form a chamber containing material 144 dispensedby material dispenser 142. Patterned energy, directed by the image relay120, can melt, fuse, sinter, amalgamate, change crystal structure,influence stress patterns, or otherwise chemically or physically modifythe dispensed material 144 to form structures with desired properties.

Energy source 112 generates photon (light), electron, ion, or othersuitable energy beams or fluxes capable of being directed, shaped, andpatterned. Multiple energy sources can be used in combination. Theenergy source 112 can include lasers, incandescent light, concentratedsolar, other light sources, electron beams, or ion beams. Possible lasertypes include, but are not limited to: Gas Lasers, Chemical Lasers, DyeLasers, Metal Vapor Lasers, Solid State Lasers (e.g. fiber),Semiconductor (e.g. diode) Lasers, Free electron laser, Gas dynamiclaser, “Nickel-like” Samarium laser, Raman laser, or Nuclear pumpedlaser.

A Gas Laser can include lasers such as a Helium-neon laser, Argon laser,Krypton laser, Xenon ion laser, Nitrogen laser, Carbon dioxide laser,Carbon monoxide laser or Excimer laser.

A Chemical laser can include lasers such as a Hydrogen fluoride laser,Deuterium fluoride laser, COIL (Chemical oxygen-iodine laser), or Agil(All gas-phase iodine laser).

A Metal Vapor Laser can include lasers such as a Helium-cadmium (HeCd)metal-vapor laser, Helium-mercury (HeHg) metal-vapor laser,Helium-selenium (HeSe) metal-vapor laser, Helium-silver (HeAg)metal-vapor laser, Strontium Vapor Laser, Neon-copper (NeCu) metal-vaporlaser, Copper vapor laser, Gold vapor laser, or Manganese (Mn/MnCl2)vapor laser.

A Solid State Laser can include lasers such as a Ruby laser, Nd:YAGlaser, NdCrYAG laser, Er:YAG laser, Neodymium YLF (Nd:YLF) solid-statelaser, Neodymium doped Yttrium orthovanadate (Nd:YVO4) laser, Neodymiumdoped yttrium calcium oxoborateNd:YCa4O(BO3)3 or simply Nd:YCOB,Neodymium glass (Nd:Glass) laser, Titanium sapphire (Ti:sapphire) laser,Thulium YAG (Tm:YAG) laser, Ytterbium YAG (Yb:YAG) laser, Ytterbium:2O3(glass or ceramics) laser, Ytterbium doped glass laser (rod, plate/chip,and fiber), Holmium YAG (Ho:YAG) laser, Chromium ZnSe (Cr:ZnSe) laser,Cerium doped lithium strontium (or calcium)aluminum fluoride (Ce:LiSAF,Ce:LiCAF), Promethium 147 doped phosphate glass (147Pm+3:Glass)solid-state laser, Chromium doped chrysoberyl (alexandrite) laser,Erbium doped anderbium-ytterbium co-doped glass lasers, Trivalenturanium doped calcium fluoride (U:CaF2) solid-state laser, Divalentsamarium doped calcium fluoride (Sm:CaF2) laser, or F-Center laser.

A Semiconductor Laser can include laser medium types such as GaN, InGaN,AlGaInP, AlGaAs, InGaAsP, GaInP, InGaAs, InGaAsO, GaInAsSb, lead salt,Vertical cavity surface emitting laser (VCSEL), Quantum cascade laser,Hybrid silicon laser, or combinations thereof.

For example, in one embodiment a single Nd:YAG q-switched laser can beused in conjunction with multiple semiconductor lasers. In anotherembodiment, an electron beam can be used in conjunction with anultraviolet semiconductor laser array. In still other embodiments, atwo-dimensional array of lasers can be used. In some embodiments withmultiple energy sources, pre-patterning of an energy beam can be done byselectively activating and deactivating energy sources.

Beam shaping unit 114 can include a great variety of imaging optics tocombine, focus, diverge, reflect, refract, homogenize, adjust intensity,adjust frequency, or otherwise shape and direct one or more energy beamsreceived from the energy source 112 toward the energy patterning unit116. In one embodiment, multiple light beams, each having a distinctlight wavelength, can be combined using wavelength selective mirrors(e.g. dichroics) or diffractive elements. In other embodiments, multiplebeams can be homogenized or combined using multifaceted mirrors,microlenses, and refractive or diffractive optical elements.

Energy patterning unit 116 can include static or dynamic energypatterning elements. For example, photon, electron, or ion beams can beblocked by masks with fixed or movable elements. To increase flexibilityand ease of image patterning, pixel addressable masking, imagegeneration, or transmission can be used. In some embodiments, the energypatterning unit includes addressable light valves, alone or inconjunction with other patterning mechanisms to provide patterning. Thelight valves can be transmissive, reflective, or use a combination oftransmissive and reflective elements. Patterns can be dynamicallymodified using electrical or optical addressing. In one embodiment, atransmissive optically addressed light valve acts to rotate polarizationof light passing through the valve, with optically addressed pixelsforming patterns defined by a light projection source. In anotherembodiment, a reflective optically addressed light valve includes awrite beam for modifying polarization of a read beam. In yet anotherembodiment, an electron patterning device receives an address patternfrom an electrical or photon stimulation source and generates apatterned emission of electrons.

Rejected energy handling unit 118 is used to disperse, redirect, orutilize energy not patterned and passed through the energy pattern imagerelay 120. In one embodiment, the rejected energy handling unit 118 caninclude passive or active cooling elements that remove heat from theenergy patterning unit 116. In other embodiments, the rejected energyhandling unit can include a “beam dump” to absorb and convert to heatany beam energy not used in defining the energy pattern. In still otherembodiments, rejected beam energy can be recycled using beam shapingoptics 114. Alternatively, or in addition, rejected beam energy can bedirected to the article processing unit 140 for heating or furtherpatterning. In certain embodiments, rejected beam energy can be directedto additional energy patterning systems or article processing units.

Image relay 120 receives a patterned image (typically two-dimensional)from the energy patterning unit 116 and guides it toward the articleprocessing unit 140. In a manner similar to beam shaping optics 114, theimage relay 120 can include optics to combine, focus, diverge, reflect,refract, adjust intensity, adjust frequency, or otherwise shape anddirect the patterned image.

Article processing unit 140 can include a walled chamber 148 and bed144, and a material dispenser 142 for distributing material. Thematerial dispenser 142 can distribute, remove, mix, provide gradationsor changes in material type or particle size, or adjust layer thicknessof material. The material can include metal, ceramic, glass, polymericpowders, other melt-able material capable of undergoing a thermallyinduced phase change from solid to liquid and back again, orcombinations thereof. The material can further include composites ofmelt-able material and non-melt-able material where either or bothcomponents can be selectively targeted by the imaging relay system tomelt the component that is melt-able, while either leaving along thenon-melt-able material or causing it to undergo avaporizing/destroying/combusting or otherwise destructive process. Incertain embodiments, slurries, sprays, coatings, wires, strips, orsheets of materials can be used. Unwanted material can be removed fordisposable or recycling by use of blowers, vacuum systems, sweeping,vibrating, shaking, tipping, or inversion of the bed 146.

In addition to material handling components, the article processing unit140 can include components for holding and supporting 3D structures,mechanisms for heating or cooling the chamber, auxiliary or supportingoptics, and sensors and control mechanisms for monitoring or adjustingmaterial or environmental conditions. The article processing unit can,in whole or in part, support a vacuum or inert gas atmosphere to reduceunwanted chemical interactions as well as to mitigate the risks of fireor explosion (especially with reactive metals).

Control processor 150 can be connected to control any components ofadditive manufacturing system 100. The control processor 150 can beconnected to variety of sensors, actuators, heating or cooling systems,monitors, and controllers to coordinate operation. A wide range ofsensors, including imagers, light intensity monitors, thermal, pressure,or gas sensors can be used to provide information used in control ormonitoring. The control processor can be a single central controller, oralternatively, can include one or more independent control systems. Thecontroller processor 150 is provided with an interface to allow input ofmanufacturing instructions. Use of a wide range of sensors allowsvarious feedback control mechanisms that improve quality, manufacturingthroughput, and energy efficiency.

FIG. 1B is a cartoon illustrating a bed 146 that supports material 144.Using a series of sequentially applied, two-dimensional patterned energybeam images (squares in dotted outline 124), a structure 149 isadditively manufactured. As will be understood, image patterns havingnon-square boundaries can be used, overlapping or interpenetratingimages can be used, and images can be provided by two or more energypatterning systems. In other embodiments, images can be formed inconjunction with directed electron or ion beams, or with printed orselective spray systems.

FIG. 2 is a flow chart illustrating one embodiment of an additivemanufacturing process supported by the described optical and mechanicalcomponents. In step 202, material is positioned in a bed, chamber, orother suitable support. The material can be a powder capable of beingmelted, fused, sintered, induced to change crystal structure, havestress patterns influenced, or otherwise chemically or physicallymodified to form structures with desired properties.

In step 204, unpatterned energy is emitted by one or more energyemitters, including but not limited to solid state or semiconductorlasers, or electrical power supply flowing electrons down a wire. Instep 206, the unpatterned energy is shaped and modified (e.g. intensitymodulated or focused). In step 208, this unpatterned energy ispatterned, with energy not forming a part of the pattern being handledin step 210 (this can include conversion to waste heat, or recycling aspatterned or unpatterned energy). In step 212, the patterned energy, nowforming a two-dimensional image is relayed toward the material. In step214, the image is applied to the material, building a portion of a 3Dstructure. These steps can be repeated (loop 218) until the image (ordifferent and subsequent image) has been applied to all necessaryregions of a top layer of the material. When application of energy tothe top layer of the material is finished, a new layer can be applied(loop 216) to continue building the 3D structure. These process loopsare continued until the 3D structure is complete, when remaining excessmaterial can be removed or recycled.

FIG. 3A is one embodiment of an additive manufacturing system 300 thatuses multiple semiconductor lasers as part of an energy patterningsystem 310. A control processor 350 can be connected to variety ofsensors, actuators, heating or cooling systems, monitors, andcontrollers to coordinate operation of multiple lasers 312, lightpatterning unit 316, and image relay 320, as well as any other componentof system 300. These connections are generally indicated by a dottedoutline 351 surrounding components of system 300. As will beappreciated, connections can be wired or wireless, continuous orintermittent, and include capability for feedback (for example, thermalheating can be adjusted in response to sensed temperature). The multiplelasers 312 can emit a beam 301 of light at a 1000 nm wavelength that,for example, is 90 mm wide by 20 mm tall. The beam 301 is resized byimaging optics 370 to create beam 303. Beam 303 is 6 mm wide by 6 mmtall, and is incident on light homogenization device 372 which blendslight together to create blended beam 305. Beam 305 is then incident onimaging assembly 374 which reshapes the light into beam 307 and is thenincident on hot cold mirror 376. The mirror 376 allows 1000 nm light topass, but reflects 450 nm light. A light projector 378 capable ofprojecting low power light at 1080p pixel resolution and 450 nm emitsbeam 309, which is then incident on hot cold mirror 376. Beams 307 and309 overlay in beam 311, and both are imaged onto optically addressedlight valve 380 in a 20 mm wide, 20 mm tall image. Images formed fromthe homogenizer 372 and the projector 378 are recreated and overlaid onlight valve 380.

The optically addressed light valve 380 is stimulated by the light(typically ranging from 400-500 nm) and imprints a polarization rotationpattern in transmitted beam 313 which is incident upon polarizer 382.The polarizer 382 splits the two polarization states, transmittingp-polarization into beam 317 and reflecting s-polarization into beam 315which is then sent to a beam dump 318 that handles the rejected energy.As will be understood, in other embodiments the polarization could bereversed, with s-polarization formed into beam 317 and reflectingp-polarization into beam 315. Beam 317 enters the final imaging assembly320 which includes optics 384 that resize the patterned light. This beamreflects off of a movable mirror 386 to beam 319, which terminates in afocused image applied to material bed 344 in an article processing unit340. The depth of field in the image selected to span multiple layers,providing optimum focus in the range of a few layers of error or offset.

The bed 390 can be raised or lowered (vertically indexed) within chamberwalls 388 that contain material 344 dispensed by material dispenser 342.In certain embodiments, the bed 390 can remain fixed, and optics of thefinal imaging assembly 320 can be vertically raised or lowered. Materialdistribution is provided by a sweeper mechanism 392 that can evenlyspread powder held in hopper 394, being able to provide new layers ofmaterial as needed. An image 6 mm wide by 6 mm tall can be sequentiallydirected by the movable mirror 386 at different positions of the bed.

When using a powdered ceramic or metal material in this additivemanufacturing system 300, the powder can be spread in a thin layer,approximately 1-3 particles thick, on top of a base substrate (andsubsequent layers) as the part is built. When the powder is melted,sintered, or fused by a patterned beam 319, it bonds to the underlyinglayer, creating a solid structure. The patterned beam 319 can beoperated in a pulsed fashion at 40 Hz, moving to the subsequent 6 mm ×6mm image locations at intervals of 10 ms to 0.5 ms (with 3 to 0.1 msbeing desirable) until the selected patterned areas of powder have beenmelted. The bed 390 then lowers itself by a thickness corresponding toone layer, and the sweeper mechanism 392 spreads a new layer of powderedmaterial. This process is repeated until the 2D layers have built up thedesired 3D structure. In certain embodiments, the article processingunit 340 can have a controlled atmosphere. This allows reactivematerials to be manufactured in an inert gas, or vacuum environmentwithout the risk of oxidation or chemical reaction, or fire or explosion(if reactive metals are used).

FIG. 3B illustrates in more detail operation of the light patterningunit 316 of FIG. 3A. As seen in FIG. 3B, a representative input pattern333 (here seen as the numeral “9”) is defined in an 8×12 pixel array oflight projected as beam 309 toward mirror 376. Each grey pixelrepresents a light filled pixel, while white pixels are unlit. Inpractice, each pixel can have varying levels of light, includinglight-free, partial light intensity, or maximal light intensity.Unpatterned light 331 that forms beam 307 is directed and passes througha hot/cold mirror 376, where it combines with patterned beam 309. Afterreflection by the hot/cold mirror 376, the patterned light beam 311formed from overlay of beams 307 and 309 in beam 311, and both areimaged onto optically addressed light valve 380. The optically addressedlight valve 380, which would rotate the polarization state ofunpatterned light 331, is stimulated by the patterned light beam 309,311 to selectively not rotate the polarization state of polarized light307, 311 in the pattern of the numeral “9” into beam 313. The unrotatedlight representative of pattern 333 in beam 313 is then allowed to passthrough polarizer mirror 382 resulting in beam 317 and pattern 335.Polarized light in a second rotated state is rejected by polarizermirror 382, into beam 315 carrying the negative pixel pattern 337consisting of a light-free numeral “9”.

Other types of light valves can be substituted or used in combinationwith the described light valve. Reflective light valves, or light valvesbase on selective diffraction or refraction can also be used. In certainembodiments, non-optically addressed light valves can be used. These caninclude but are not limited to electrically addressable pixel elements,movable mirror or micro-mirror systems, piezo or micro-actuated opticalsystems, fixed or movable masks, or shields, or any other conventionalsystem able to provide high intensity light patterning. For electronbeam patterning, these valves may selectively emit electrons based on anaddress location, thus imbuing a pattern on the beam of electronsleaving the valve.

FIG. 3C is one embodiment of an additive manufacturing system thatincludes a switchyard system enabling reuse of patterned two-dimensionalenergy. Similar to the embodiment discussed with respect to FIG. 1A, anadditive manufacturing system 220 has an energy patterning system withan energy source 112 that directs one or more continuous or intermittentenergy beam(s) toward beam shaping optics 114. After shaping, the beamis two-dimensionally patterned by an energy patterning unit 230, withgenerally some energy being directed to a rejected energy handling unit222. Patterned energy is relayed by one of multiple image relays 232toward one or more article processing units 234A, 234B, 234C, or 234D,typically as a two-dimensional image focused near a movable or fixedheight bed. The bed (with optional walls) can form a chamber containingmaterial dispensed by material dispenser. Patterned energy, directed bythe image relays 232, can melt, fuse, sinter, amalgamate, change crystalstructure, influence stress patterns, or otherwise chemically orphysically modify the dispensed material to form structures with desiredproperties.

In this embodiment, the rejected energy handling unit has multiplecomponents to permit reuse of rejected patterned energy. Relays 228A,228B, and 22C can respectively transfer energy to an electricitygenerator 224, a heat/cool thermal management system 225, or an energydump 226. Optionally, relay 228C can direct patterned energy into theimage relay 232 for further processing. In other embodiments, patternedenergy can be directed by relay 228C, to relay 228B and 228A forinsertion into the energy beam(s) provided by energy source 112. Reuseof patterned images is also possible using image relay 232. Images canbe redirected, inverted, mirrored, sub-patterned, or otherwisetransformed for distribution to one or more article processing units234A-D. Advantageously, reuse of the patterned light can improve energyefficiency of the additive manufacturing process, and in some casesimprove energy intensity directed at a bed, or reduce manufacture time.

FIG. 3D is a cartoon 235 illustrating a simple geometricaltransformation of a rejected energy beam for reuse. An input pattern 236is directed into an image relay 237 capable of providing a mirror imagepixel pattern 238. As will be appreciated, more complex pixeltransformations are possible, including geometrical transformations, orpattern remapping of individual pixels and groups of pixels. Instead ofbeing wasted in a beam dump, this remapped pattern can be directed to anarticle processing unit to improve manufacturing throughput or beamintensity.

FIG. 3E is a cartoon 235 illustrating multiple transformations of arejected energy beam for reuse. An input pattern 236 is directed into aseries of image relays 237B-E capable of providing a pixel pattern 238.

FIGS. 3F & 3G are non-light-based systems, 3H-3M are mixed mode withaspects of light and electron beam-based systems. FIG. 3F is an electronbeam-based system 240 that includes a patterned electron beam 241capable of producing, for example, a “P” shaped pixel image. A highvoltage electricity power system 243 is connected to an addressablecathode unit 245. In some embodiments, the cathode unit can be addressedby an optical image projection. In other embodiments, it can beaddressed by a moving electron beam projection, and in yet otherembodiments it can be electronically addressed. In response toapplication of a two-dimensional patterned image by projector 244, thecathode unit 245 is stimulated to emit electrons wherever the patternedimage is optically addressed. Focusing of the electron beam pattern isprovided by an image relay system 247 that includes imaging coils 246Aand 246B. Final positioning of the patterned image is provided by adeflection coil 248 that is able to move the patterned image to adesired position on a bed of additive manufacturing component 249.

In another embodiment supporting light recycling and reuse, multiplexmultiple beams of light from one or more light sources are provided. Themultiple beams of light may be reshaped and blended to provide a firstbeam of light. A spatial polarization pattern may be applied on thefirst beam of light to provide a second beam of light. Polarizationstates of the second beam of light may be split to reflect a third beamof light, which may be reshaped into a fourth beam of light. The fourthbeam of light may be introduced as one of the multiple beams of light toresult in a fifth beam of light. In effect, this or similar systems canreduce energy costs associated with an additive manufacturing system. Bycollecting, beam combining, homogenizing and re-introducing unwantedlight rejected by a spatial polarization valve or light valve operatingin polarization modification mode, overall transmitted light power canpotentially be unaffected by the pattern applied by a light valve. Thisadvantageously results in an effective re-distribution of the lightpassing through the light valve into the desired pattern, increasing thelight intensity proportional to the amount of area patterned.

Combining beams from multiple lasers into a single beam is one way toincreasing beam intensity. In one embodiment, multiple light beams, eachhaving a distinct light wavelength, can be combined using eitherwavelength selective mirrors or diffractive elements. In certainembodiments, reflective optical elements that are not sensitive towavelength dependent refractive effects can be used to guide amultiwavelength beam.

Patterned light can be directed using movable mirrors, prisms,diffractive optical elements, or solid state optical systems that do notrequire substantial physical movement. In one embodiment, amagnification ratio and an image distance associated with an intensityand a pixel size of an incident light on a location of a top surface ofa powder bed can be determined for an additively manufactured,three-dimensional (3D) print job. One of a plurality of lens assembliescan be configured to provide the incident light having the magnificationratio, with the lens assemblies both a first set of optical lenses and asecond sets of optical lenses, and with the second sets of opticallenses being swappable from the lens assemblies. Rotations of one ormore sets of mirrors mounted on compensating gantries and a final mirrormounted on a build platform gantry can be used to direct the incidentlight from a precursor mirror onto the location of the top surface ofthe powder bed. Translational movements of compensating gantries and thebuild platform gantry are also able to ensure that distance of theincident light from the precursor mirror to the location of the topsurface of the powder bed is substantially equivalent to the imagedistance. In effect, this enables a quick change in the optical beamdelivery size and intensity across locations of a build area fordifferent powdered materials while ensuring high availability of thesystem.

In certain embodiments, a plurality of build chambers, each having abuild platform to hold a powder bed, can be used in conjunction withmultiple optical-mechanical assemblies arranged to receive and directthe one or more incident energy beams into the build chambers. Multiplechambers allow for concurrent printing of one or more print jobs insideone or more build chambers. In other embodiments, a removable chambersidewall can simplify removal of printed objects from build chambers,allowing quick exchanges of powdered materials. The chamber can also beequipped with an adjustable process temperature controls.

In another embodiment, one or more build chambers can have a buildchamber that is maintained at a fixed height, while optics arevertically movable. A distance between final optics of a lens assemblyand a top surface of powder bed a may be managed to be essentiallyconstant by indexing final optics upwards, by a distance equivalent to athickness of a powder layer, while keeping the build platform at a fixedheight. Advantageously, as compared to a vertically moving the buildplatform, large and heavy objects can be more easily manufactured, sinceprecise micron scale movements of the build platform are not needed.Typically, build chambers intended for metal powders with a volume morethan ˜0.1-0.2 cubic meters (i.e., greater than 100-200 liters or heavierthan 500-1,000 kg) will most benefit from keeping the build platform ata fixed height.

In one embodiment, a portion of the layer of the powder bed may beselectively melted or fused to form one or more temporary walls out ofthe fused portion of the layer of the powder bed to contain anotherportion of the layer of the powder bed on the build platform. Inselected embodiments, a fluid passageway can be formed in the one ormore first walls to enable improved thermal management.

Improved powder handling can be another aspect of an improved additivemanufacturing system. A build platform supporting a powder bed can becapable of tilting, inverting, and shaking to separate the powder bedsubstantially from the build platform in a hopper. The powdered materialforming the powder bed may be collected in a hopper for reuse in laterprint jobs. The powder collecting process may be automated, andvacuuming or gas jet systems also used to aid powder dislodgement andremoval

Some embodiments of the disclosed additive manufacturing system can beconfigured to easily handle parts longer than an available chamber. Acontinuous (long) part can be sequentially advanced in a longitudinaldirection from a first zone to a second zone. In the first zone,selected granules of a granular material can be amalgamated. In thesecond zone, unamalgamated granules of the granular material can beremoved. The first portion of the continuous part can be advanced fromthe second zone to a third zone, while a last portion of the continuouspart is formed within the first zone and the first portion is maintainedin the same position in the lateral and transverse directions that thefirst portion occupied within the first zone and the second zone. Ineffect, additive manufacture and clean-up (e.g., separation and/orreclamation of unused or unamalgamated granular material) may beperformed in parallel (i.e., at the same time) at different locations orzones on a part conveyor, with no need to stop for removal of granularmaterial and/or parts.

In another embodiment, additive manufacturing capability can be improvedby use of an enclosure restricting an exchange of gaseous matter betweenan interior of the enclosure and an exterior of the enclosure. Anairlock provides an interface between the interior and the exterior;with the interior having multiple additive manufacturing chambers,including those supporting power bed fusion. A gas management systemmaintains gaseous oxygen within the interior at or below a limitingoxygen concentration, increasing flexibility in types of powder andprocessing that can be used in the system.

In another manufacturing embodiment, capability can be improved byhaving a 3D printer contained within an enclosure, the printer able tocreate a part having a weight greater than or equal to 2,000 kilograms.A gas management system may maintain gaseous oxygen within the enclosureat concentrations below the atmospheric level. In some embodiments, awheeled vehicle may transport the part from inside the enclosure,through an airlock, since the airlock operates to buffer between agaseous environment within the enclosure and a gaseous environmentoutside the enclosure, and to a location exterior to both the enclosureand the airlock.

Other manufacturing embodiments involve collecting powder samples inreal-time in a powder bed fusion additive manufacturing system. Aningester system is used for in-process collection and characterizationsof powder samples. The collection may be performed periodically and theresults of characterizations result in adjustments to the powder bedfusion process. The ingester system can optionally be used for one ormore of audit, process adjustments or actions such as modifying printerparameters or verifying proper use of licensed powder materials.

Yet another improvement to an additive manufacturing process can beprovided by use of a manipulator device such as a crane, lifting gantry,robot arm, or similar that allows for the manipulation of parts thatwould be difficult or impossible for a human to move is described. Themanipulator device can grasp various permanent or temporary additivelymanufactured manipulation points on a part to enable repositioning ormaneuvering of the part.

FIG. 3H illustrates an exemplary of a high-speed electron beam addressedreflective light valve (EBA-RLV, 100B) where 110B is an exemplary of theEBA-RLV device. 110B is composed of an secondary emission grid or plane(115B) which collects negative charges which either are scattered offthe surface of the structured electrical via (aka via) array (120B, anelectrical via is an array of electrical conduction through aninsulative plane of material), emit from 120B from a ballistic charge,or are pulled off as a function of 120B's voltage. 115B allows 120B tocharge a ‘pixel’ defined by the electron beam to have a positive,neutral or negative charge and allows the pixel to be better definedthan those systems without such a screen. The secondary emission gridcreates both positive and negative voltages and thus positive andnegative fields are transmitted by the structured via to theelectro-optic layer. The positive and negative fields allow for fringefield switching and in-plane switching modes in the linear electro-opticlayer (150B) that can be composed of appropriate liquid crystal orsimilar materials. The via layer (120B) can be structured by being madeof anisotropic matrix in which platelet conductive particles arescattered throughout its volume, a silicon or polymer based electricalvia array commonly used in microelectronics as a fanout interlayer, orflex layer with similar arrangements of microscopic or nanoscopicthrough conduction paths. Attached to 120B is a High Reflective Mirror(HRM, 130B) which is >99% reflective for 990-1070 nm light. Attached to130B is an alignment or impedance layer (140B) which sets up theorientation of the Linear Electro-Optic layer (LEO, 150B). An additionalalignment/impedance layer (160B) aids in defining the orientation of150B. A Transparent Conductive Oxide (TCO, 170B) terminates 110B'selectrical circuit composed of 115B, 120B, 130B, 140B, 150B, and 160B. Asupporting substrate (180B) provides stability for 110B.

The electron source which defines a pixel in 110B is generated by anelectron gun (can also be a tunneling electron source, a Spindt typecold cathode emitter or similar electron beam generator) which emits astream of free electrons (200B). Deflection and focusing structuresallow the beam to be swept in the “x” (210B) and “y” (220B) directionsacross the face of 115B, which in tandem with 115B defines chargedpixels in 120B and varying voltage fields across 150B. Modulating thestrength of 200B along with the waveform imposed on 115B allows for grayscale imagery to be imposed on 150B. The current and voltage control for190B is conveyed to 190B by way of control line 230B from the electronbeam electronics module (270B). Likewise, the control of the voltagewaveform for 210B and 220B are conveyed by control lines 240B and 250B,respectively from 260B (X-Y deflection driver) controlled by 270B. Inaddition, 270B controls the voltage and current waveform of 115B by wayof 280B control line. 270B is controlled by the LV electronics module(290B) which also controls the voltage waveform of 170B by way of 300Bcontrol line.

The way that 110B works as a light valve requires that an unpatternedhigh fluence beam (310B) enters 110B by passing through 180B, 170B,160B, 150B 140B and reflecting off 130B before traversing 140B, 150B,160B, 170B and exiting 180B. The charge image that is deposited by theraster scanning 200B across 115B and 120B is transferred as a voltageimage across 150B. This voltage image acts upon 150B causing its opticalresponse to change. The optical response of 150B is usually a change inits birefringence but can also be a phase change, spectral, scattering,absorption, or reflection response as seen by 310B. The voltage imageimposes an optical response image on 150B, the double passage of 310Bthrough 150B imposes that image onto 310B changing it to a patterned HFLbeam (320B). 320B passes out of 110B and strikes the beam patternseparator (330B) which splits the desired pattern image (370B) from theundesired image. The desired image (370B) is relayed to the printchamber while the undesired image (not shown) goes to either a beam dumpor a switchyard system.

In the situation where an unpatterned HLF beam (340B) enters 100B wherethere is no image presented by the electron beam system, this light isnot affected and not patterned by 110B and exits unpatterned (350B) andupon striking 330B, is diverted into 360B as it is sent to either a beamdump or a switchyard system. The frame rates of an EBA-RLV system canexceed 1 MHz frame rate and would be likely limited by the switch timeof 150B than the capabilities of the scanning electron beam electronics.

FIG. 3I illustrates an example of an embodiment of the EBA-RLV byincorporating an electron beam array such as a Spindt array, or anyversion of an addressable 2D cold cathode electron emitter, orintegrated emission array such as the one described in 100B-ii. Thisembodiment is composed of an electron beam addressed reflective lightvalve as described in FIG. 1B in addition to other components describedbelow. 110B-ii is activated by a 2D addressable electron emitters (120B)which contain rows and columns of separately addressable field emitters(125B-ii) in an active matrix arrangement. Activation of one suchemitter (125B-ii) allows electron emission (127B-ii) to be locallydeposited onto 110B-ii so that a charged pixel (130B-ii) is generatedand a modification of the LEO layer within 110B-ii) is affected. The rowand column addressing of 120B-ii is controlled by an electron beam arraydriver(160B-ii) and is conveyed to 120B-ii by control lines 140B-ii(column control lines) and 150B-ii (row control lines). A LV electronicscontrols 160B-ii including the voltage waveform imposed on the TCOinside 110B-ii via the control line 180B-ii. As described in FIG. 1B, anincoming unpatterned HFL (190B-ii) enters 110B-ii and leaves as apatterned HFL (200B-ii) wherever an electron beam pixel has beenactivated. 200B-ii is split by beam pattern separator (210B-ii) into thedesired patterned HFL beam (220B-ii), which is imaged to the printchamber, and an undesired pattern that goes into a beam dump or aswitchyard system. If a unpatterned HFL beam (230B-ii) enters 110B-iiwhere there is no electron beam pixel is activated, it will leave110B-ii as an unpatterned HFL beam (240B-ii) and be totally rejected by210B-ii and be directed to either a beam dump or a switchyard system as250B-ii. The frame rate of a 2D addressable EBA-RLV is limited by thearray drivers, typically 100 Hz frame rate.

FIG. 3J illustrates an example of an embodiment of the EBA-RLV byincorporating a photoconducting separating layer between the gate anodeand the tip entrance and making the base of the cathode emission arraytransparent to a Write Beam. This enhancement would turn the EBA-RLVinto an optically addressed EBA-RLV as shown in 110B-iii. The EBA-RLV(110B-iii) components is described in FIG. 1B. In this embodiment thescanning electron beam is replaced by an optically addressed coldcathode emitter array (113B-iii) which includes a photoconductor(120B-iii) separating the anode from the tip support structure. In thisembodiment, a patterned write beam (115B-iii) at λ2 passes through113B-iii and activates the photoconductor 125B-iii allowing the tipdirectly below 125B-iii to emit a stream of electrons (127B-iii) whichcreates a patterned charged area (130B-iii) within 110B-iii that mirrorsthe pattern in 115B-iii. The charged pattern transfers a voltage fromthe outside of 110B-iii to across the LEO layer within 110B-iii. Thecontrol lines 140B-iii, 150B-iii, and 153B-iii which control the voltagewaveforms impressed onto the cold cathode array, the photoconductoranode layer, and the secondary emission grid within 110B-iii,respectively. The electron beam array electronics (155B-iii) control thewaveforms on 140B-iii, 150B-iii, and 153B-iii and works in conjunctionwith the LV electronics (157B-iii) which also controls the waveformdelivered to the TCO inside 110B-iii via control line 160B-iii.

The desired pattern is imposed onto the HFL beam by initially having anunpatterned HFL beam (170B-iii) enter 110B-iii and interact with the LEOthat has been activated by 115B-iii by way of 126B-iii, 127B-iii and130B-iii. The LEO impresses the same pattern as that inherent in115B-iii onto 170B-iii and upon reflection off 110B-iii's HRM, leaves110B-iii as a patterned HFL beam (180B-iii). The patterned HFL beam(180B-iii) strikes the pattern separator (190B-iii) and the desired beam(200B-iii) is relayed to the print chamber while the unwanted patterngoes into either a beam dump or a switchyard system. As is in priorcases, an unpatterned HFL beam (210B-iii) entering 110B-iii in an areanot activated, the beam reflects of the HRM inside 110B-iii and leavesthe EBA-RLV still unpatterned as 220B-iii where it is fully rejected by190B-iii and becomes 230B-iii which goes into either a beam dump or aswitchyard system. The benefit of 100B-iii is that the frame rate isdependent on the speed at which 115B-iii and the LEO material can beswitched and in the case for LiNbO3 as the LEO material and a fast DLPsystem as the source for 115B-iii, 100B-iii is limited to the 50-100 KHzframe rate limitation inherent in a Digital Light Projection (DLP) orsimilar optical projection system.

FIG. 3K illustrates an example of an optically addressed electron beamprint engine (100 x) which emits transfers an optical pattern of lowintensity to high energy patterned array of electron beams that areparallelized to powder bed upon which a molten pool pattern is formed inthe powder that reflects what was in the optical beam. The opticallyaddressed print head (110 x) is composed of an array of cold cathode(120 x) field emitters such as a Spindt array or similar solid-statefield emission array but constructed to react to a patterned opticalbeam. The field emission array is composed of a TCO (130 x), an array offield emission tips (140 x) electrically connected to 130 x andoptically and electrically isolated from each other. At the top of thefield emitter well is a photoconductor anode (150 x). Electron focusinggrids (160 x and 170 x) sit above 150 x and are used to focus theemitted electrons to the powder bed surface 220 x. A patterned lowfluence optical beam (180 x) travels through 130X and is at a wavelengththat passes through the 140 x and the surrounding well material beforeactivating 150 x. An example of this activation is the pixel shown as190 x. The activation of 150 x at 190 x causes the normal field seen byany one 140 x to drop slightly but enough for electrons to tunnelthrough the field emission tip into the environment, limited by vacuumbreakdown and the strength of the tip material. The quantum mechanicalnature of this tunneling produces very little-to-no heat at the tip thuseach emitter can support uA to mA of current without long term effect.Additionally, the tunneling effect has an exponential response to thevoltage drop so there is little to no ramping up to this threshold, likea transistor turn-on. The electron beam produced (200 x) containssufficiently high amounts of energy as to melt the powder when itinteracts with it at 220 x. Extinguishing 180 x quickly extinguishes thesource of electrons from 200 s and 210 x freezes into a solid part tobecome part of the build (230 x).

The control for the electron beam print engine is managed by theelectron beam array electronics (240 x) and overall control line 250 xto 110 x. Various control lines for 130 x, 150 x, 160 x, and 170 x arecontrolled by 260 x, 270 x, 280 x, and 290 x, respectively. A chargereturn (300 x) is connected to 210 x by way of previously melted and nowsolidified material within 230 x.

FIG. 3L illustrates an embodiment of an optically addressed electronbeam print head with a 2D electrically addressed scanner (100 y). Theoptically addressed electron beam print head (110 y) is coupled with aX-deflection array (130 y) and a Y-deflection array (140 y) creating anensemble of scanning grids to allow for the focused electron beam pixelto be scanned in 1 or 2D space across the print bed. The X-deflectionarray (130 y) and Y-deflection array (140 y) can be integrated into theelectron beam print head (110 y) or constructed of separate structuresand then later integrated. Combining focus control with 2D scanningallows for scanning in 3D (3 Dimensions) allowing for sub-surfacemelting. These deflection arrays operate on the ensemble of fieldemission elements and can be either integrated into the opticallyaddressed field emission array or as discrete array elements as depictedhere.

As before, a write beam operating at λ2 illuminates one (or more) fieldemission elements and activates the photoconductive layer controllingthe tip(s) electron emission (175 y) which enters 130 y and 140 y array.Activation of 130 y and 140 y causes 175 y to deflect into 180 y whichstrikes the powder bed (150 y) residing on previously melted (nowsolidified) features (160 y) creating a melt pool 190 y. Activation of130 y and 140 y is performed by applying voltage Vx1 to 130 y and Vy1 to140 y which results in 180 y hitting 150 y at 190 y. By applyingdifferent voltages to 130 y and 140 y, 175 y can be steered to differentpositions on 150 y. Thus if 170 y represents a patterned image, thispatterned image is transferred into a patterned electron beam image andthe image can be placed at different positions on 150 y via applicationsof different voltages applied to 130 y and 140 y. Two examples are shownin which 175 is steered into 200 y by applying Voltage Vx2 onto 130 yand Vy2 onto 140 y so that 175 y becomes 200 y and is steered to land on150 y at 210 y. Likewise if voltage Vx3 and Vy3 are applied to 130 y and140 y (respectively), then 175 y is steered into 220 y which is thenplaced at position 230 y on 150 y where it will create a melt pool. Asbefore, electron beam array electronic control the optically addressedelectron beam print head with this embodiment requiring additionalelectronics to control the X-Y deflection arrays shown as 250 y withcontrol line for X deflection (260 y) and y-deflection (270 y).

FIG. 3M illustrates an embodiment of an optically addressed electronbeam print head 2D scanner (100 z) in which the X and Y deflectionarrays are also optically controlled. As before the optically addressedelectron beam emission array (print head) contains the opticallyactivated field emitter via a photoconductive layer in 110 z withfocusing optics (electrically activated). In this embodiment, the globalelectrical control of the X-deflection and Y-deflection arrays arereplaced with optically activated photoconductive features which isolatethe voltage supply to individual channels within these arrays. Thesechannels are associated with individual field emitters (or groups ofthem). While the activation of the field emitter at any one pixel(defined by one emitter or group of emitters) is performed as before byilluminating 110 z with a write beam (170 z) operating at λ2. Thiscreates an electron emission which is focused by 110 z and enters the Xdeflection array (130 z) and Y deflection array (140 z). Control overthe amount of deflection comes from two control beams, 180 z (operatingat λ3), and 190 z (operating at λ4) for the X-deflection andY-deflection, respectively. As an example, with intensity Ix1 on 180 zand intensity Iy1 on 190 z, the emission created by 170 z interactingwith 110 z will generated a deflected electron emission of 200 z whichwill land on the powder bed (150 z) at position 210 z. For an intensityIx2 and Iy2 for 180 z and 190 z (respectively), 200 z will be steeredinto 220 z which will place the electron emission at position 230 z on150 z. Likewise, for an intensity Ix3 and Iy3 for 180 z and 190 z(respectively), 200 z will be steered into 240 z which will place theelectron emission at position 250 z on 150 z. As before, the electronbeam electronics (260 z) supplies voltage and current to 110 z and areturn from the build plate while the electron beam deflectionelectronics (270 z) supplies voltage and current to 130 z and 140 z byway of voltage supply lines 280 z and 290 z, respectively. This entirestructure is item 245 in FIG. 3G and allows that system to properlyimage a distributed electron beam source to a print bed that can beplaced further away from the print bed ensuring much longer life on theelectron beam print head due to reduction of soot and evaporantdeposition during melt.

In view of the above description of FIG. 3H-FIG. 3M, some of thefeatures of the present disclosure may be summarized here. Firstly, anelectron beam may be utilized to pattern a reflective light valve (e.g.,for controlling optical beams). For instance, the electron beam may bescanned by controlling the emission from a single cathode (e.g., asshown in FIG. 3H). Moreover, the electron beam may be emitted from anarray of cathodes. In some implementations, the array of cathodes may becontrolled by an electrically addressed array (e.g., as shown in FIG.31). Alternatively, or additionally, the array of cathodes may becontrolled by an optically addressed signal interacting with aphotoconductor (e.g., as shown in FIG. 3J). Secondly, an optical beammay be utilized to control emission from a cathode array by using aphotoconductor and a focusing grid to focus (e.g., with 1:1 ratio) theoptical beam onto a target (e.g., a powder bed for additivemanufacturing). Thirdly, a photoconductor may be utilized to control, ona per-pixel basis, a 3D positioning of each pixel (e.g., as shown inFIG. 3M), an example of which being the addressable cathode unit 245shown in FIG. 3F. Fourthly, an electronically addressed grid may beutilized to control, on a per-pixel basis, the system of FIG. 3M andFIG. 3F. In some implementations, the system of FIG. 3M and FIG. 3F maybe integrated with that shown in FIG. 3H to control the positioning ofan image on the powder bed. The system of FIG. 3M and FIG. 3F may benecessary to correct or otherwise compensate for a distortion caused bythe focusing coils shown in FIG. 3F. Lastly, some or all of theaforementioned features/systems may be utilized in combination toperform 3D printing.

FIG. 4 illustrates an example optical assembly 400 of polarizationcombining to achieve up to 2× of the original semiconductor laserintensity (in the limit) in accordance with the present disclosure.Optical assembly 400 may include some or all of those components shownin FIG. 4, to be described below.

Light sources 1 and 2 are each used as a high power photon source. Insome embodiments, light sources 1 and 2 may be semiconductor laserarrays with 33.3 kW of power each, emitting photons at 1000 nm that areshaped and blended into a square beam 20 mm wide×20 mm. Emitted lightmay be 90% polarized in state p resulting in light beams 3 and 4. Theemitted light beams 3 and 4 may be incident on polarizers 5 and 6,respectively. Polarizers 5 and 6 may reflect s-polarization to result inlight beams 9 and 10, which may be incident on a beam dump 11.Polarizers 5 and 6 may transmit p-polarization to result in light beams6 and 7, which may be incident on polarization rotating opticallyaddressed light valves 12 and 13, respectively. Each of light valves 12and 13 may have the same image applied to light beams 6 and 7 to createpolarization patterns, and may spatially flip 20% of the “pixels” fromp-polarization to s-polarization in the desired patterns resulting inlight beams 14 and 15. Beams 14 and 15 may be incident on polarizers 16and 17, respectively. Polarizers 16 and 17 may reflect s-polarization toresult in light beams 18 and 19, respectively, which may contain 20% ofthe energy and may be dumped to a beam dump 20. Polarizers 16 and 17 maytransmit p-polarization to result in light beams 21 and 22. Beam 22 maybe incident on a half wave plate 23 which rotates the polarization ofevery photon by a half wave, thereby turning p-polarization tos-polarization to result in light beam 24. Beams 21 and 24 may beincident on mirrors 25 and 26, respectively, to result in light beams 27and 28. Beam 27 may be incident on mirror 29 to result in beam 30, whichmay be incident on polarizer 31 in p-polarization. Beam 28 ins-polarization may be incident on polarizer 31 which may reflects-polarization of beam 28 and transmit p-polarization of beam 30 toresult in light beam 32. Beam 32 may be a beam of twice the intensity ofa single polarization state from light source 1 or 2, for a totalinitial intensity of 1.8× the original due to the 90% initialpolarization, and proportionally less that for the 20% of thepolarization map image applied at light valves 12 and 13. Totalpropagated intensity at beam 32 may be 1.44× the initial intensity for atotal transmitted power of 47.52 kW emitted. Imaged to the original20×20 mm square, the final intensity may be 11.88 kW/cm² if divergenceangle is maintained.

FIG. 5 illustrates an example optical assembly 500 of polarizationcombining to achieve up to 100% system transmission of the originalsemiconductor laser intensity in accordance with the present disclosure.Optical assembly 500 may include some or all of those components shownin FIG. 5, to be described below.

Light sources 33 and 34 are each used as a high power photon source. Insome embodiments, light sources 33 and 34 may be semiconductor laserswith 33.3 kW of power each, emitting photons at 1000 nm that are shapedand blended into a square beam 20 mm wide×20 mm or not shaped orblended. Emitted light may be 90% polarized in p-polarization state,resulting in light beams 35 and 36. Beams 35 and 36 may be incident onpolarizers 37 and 38, respectively. Polarizers 37 and 38 may transmitp-polarization to result in light beams 39 and 40, which may be incidenton mirrors 41 and 42, respectively, to result in light beams 43 and 44.Beams 43 and 44 may be incident on mirrors 45 and 46 to result in lightbeams 47 and 48, which may be as close together as spatially allowedwithout overlap. Beams 47 and 48 may be blended together in ahomogenizer 49 to result in light beam 50, which may be incident on apolarization altering light valve 51. Light valve 51 may rotate 20%(which may be a variable based upon the desired image to be applied tolight valves 51 and 61) of the p-polarization state to s-polarization.The light leaving 51 may be incident on mirror 52 to result in lightbeam 53, which may be incident on mirror 54 to result in light beam 65.Polarizers 37 and 38 may reflect s-polarization to result in light beams55 and 56, which may be incident on mirrors 57 and 58, respectively, toresult in light beams 59 and 60. Beams 59 and 60 may be incident onmirrors 61 and 62 to result in light beams 63 and 64, respectively,which may in turn be incident on mirrors 65 and 66, respectively, toresult in light beams 67 and 68. Beams 67 and 68 may be as closetogether as spatially allowed without overlap. Beams 67 and 68 may beblended together in a homogenizer 69 to result in light beam 60, whichmay be incident on a polarization altering light valve 61. Light valve61 may rotate 20% (which may be a variable based upon the desired imageto be applied to light valves 51 and 61) of the s-polarization state top-polarization. The light leaving light valve 61 may result in lightbeam 62, which may be incident on mirror 63 and reflected into lightbeam 64. Beams 64 and 65 may be incident on polarizer 66, which mayreflect s-polarization and transmits p-polarization. The negative andun-desired image may result in light beam 67, which may be dumped to abeam-dump 68, while a resultant light beam 69 may be desired.

In optical assembly 500, the light that is dumped is the 20% rejecteddue to the patterning mechanism of light valves 51 and 61. Final laserpower may be 70% of 2*33.33 kW for 53.28 kW. Unlike optical assembly400, the comparable intensity would be over twice the area due tospatial combination of beams resulting in 6.66 kW/cm{circumflex over( )}2 if divergence angle is maintained.

In some embodiments, the two or more spatial light modulators mayinclude at least a mask or a light blocking device. In such cases, theoptical sub-assembly may be configured to combine the two or more beamsof light because of the different polarization states.

In some embodiments, the optical sub-assembly may be configured tocombine the majority polarization state and the minority polarizationstate of the two or more beams of light because of the differentpolarization states. In such cases, the two or more spatial lightmodulators may include at least a mask or a light blocking deviceconfigured to pattern each of the two or more beams of light after thecombining.

In some embodiments, the two or more spatial light modulators mayinclude two or more optically addressed light valves or two or moreliquid crystal display devices configured to apply the respectivepolarization pattern on the majority polarization state of each of thetwo or more beams of light.

In some embodiments, the optical sub-assembly may be further configuredto perform a number of operations. For instance, the opticalsub-assembly may split each of the two or more beams of light into twosplit beams each corresponding to the majority polarization state or theminority polarization state, respectively. Moreover, the opticalsub-assembly may spatially stack the split beam of each of the two ormore beams of light corresponding to the majority polarization state toprovide a first beam of light corresponding to the majority polarizationstate. Furthermore, the optical sub-assembly may spatially stack thesplit beam of each of the two or more beams of light corresponding tothe minority polarization state to provide a second beam of lightcorresponding to the minority polarization state. Additionally, theoptical sub-assembly may combine the patterned first and second beams oflight to provide the single beam of light.

In some embodiments, the two or more spatial light modulators mayinclude a first optically addressed light valve or a first liquidcrystal display device configured to apply a majority polarizationpattern on the first beam of light. Additionally, the two or morespatial light modulators may include a second optically addressed lightvalve or a second liquid crystal display device configured to apply aminority polarization pattern on the second beam of light.

In some embodiments, in spatially stacking the split beam of each of thetwo or more beams of light corresponding to the majority polarizationstate to provide the first beam of light corresponding to the majoritypolarization state, the optical sub-assembly may be configured toperform a number of operations. For instance, the optical sub-assemblymay spatially stack, by a first set of mirrors of the opticalsub-assembly, two or more split beams of the two or more beams of lightcorresponding to the majority polarization state. Moreover, the opticalsub-assembly may homogenize, by a first homogenizer of the opticalsub-assembly, the spatially stacked two or more split beams to providethe first beam of light. In some embodiments, in spatially stacking thesplit beam of each of the two or more beams of light corresponding tothe minority polarization state to provide the second beam of lightcorresponding to the minority polarization state, the opticalsub-assembly may be configured to perform a number of other operations.For instance, the optical sub-assembly may spatially stack, by a secondset of mirrors of the optical sub-assembly, two or more split beams ofthe two or more beams of light corresponding to the minoritypolarization state. Furthermore, the optical sub-assembly mayhomogenize, by a second homogenizer of the optical sub-assembly, thespatially stacked two or more split beams to provide the second beam oflight.

In some embodiments, in splitting each of the two or more beams of lightinto two split beams each corresponding to the majority polarizationstate or the minority polarization state, respectively, the opticalsub-assembly may be configured to spatially stack, by a set of mirrorsof the optical sub-assembly, the two or more beams of light prior to thesplitting. Additionally, the optical sub-assembly may split, by a set ofpolarizers of the optical sub-assembly, each of the spatially combinedtwo or more beams of light into the two split beams each correspondingto the majority polarization state or the minority polarization state,respectively.

FIG. 6 illustrates an example process 600 in accordance with the presentdisclosure. Process 600 may be utilized to realize polarizationcombining for increased intensity and efficiency in additivemanufacturing in accordance with the present disclosure. Process 600 mayinclude one or more operations, actions, or functions shown as blockssuch as 610, 620 and 630. Although illustrated as discrete blocks,various blocks of process 600 may be divided into additional blocks,combined into fewer blocks, or eliminated, depending on the desiredimplementation, and may be performed or otherwise carried out in anorder different from that shown in FIG. 6. Process 600 may beimplemented by optical assembly 400 and/or optical assembly 500, as wellas powder bed fusion additive manufacturing system 600. Process 600 maybegin with block 610.

At 610, process 600 may involve emitting two or more beams of light witha first intensity. Each of the two or more beams of light may bepolarized and may have a majority polarization state and a minoritypolarization state. Process 600 may proceed from 610 to 620.

At 620, process 600 may involve rejecting or splitting off light not inthe majority polarization state, and then applying a respectivepolarization pattern on the majority polarization state of each of thetwo or more beams of light. Process 600 may proceed from 620 to 630.

At 630, process 600 may involve combining the two or more beams of lightto provide a single beam of light with a second intensity greater thanthe first intensity.

In some embodiments, the majority polarization state and the minoritypolarization state of the two or more beams of light may be respectivelypatterned by a mask or a light blocking device. Moreover, the two ormore beams of light may be combined because of the differentpolarization states.

In some embodiments, the majority polarization state and the minoritypolarization state of the two or more beams of light may be combinedbecause of the different polarization states. Moreover, each of the twoor more beams of light may be respectively patterned by a mask or alight blocking device after the combining.

In some embodiments, in applying the respective polarization pattern onthe majority polarization state of each of the two or more beams oflight, process 600 may involve applying, by a respective one of two ormore optically addressed light valves or two or more liquid crystaldisplay devices, the respective polarization pattern on the majoritypolarization state of each of the two or more beams of light.

FIG. 7 illustrates an example process 700 in accordance with the presentdisclosure. Process 700 may be utilized to realize polarizationcombining for increased intensity and efficiency in additivemanufacturing in accordance with the present disclosure. Process 700 mayinclude one or more operations, actions, or functions shown as blockssuch as 710, 720, 730, 740, 750, 760 and 770. Although illustrated asdiscrete blocks, various blocks of process 700 may be divided intoadditional blocks, combined into fewer blocks, or eliminated, dependingon the desired implementation, and may be performed or otherwise carriedout in an order different from that shown in FIG. 7. Process 700 may beimplemented by optical assembly 400 and/or optical assembly 500, as wellas powder bed fusion additive manufacturing system 600. Process 700 maybegin with block 710.

At 710, process 700 may involve emitting two or more beams of light,each of the two or more beams of light being polarized. Process 700 mayproceed from 710 to 720.

At 720, process 700 may involve splitting each of the two or more beamsof light into two split beams each corresponding to a majoritypolarization state or a minority polarization state, respectively.Process 700 may proceed from 720 to 730.

At 730, process 700 may involve spatially stacking the split beam ofeach of the two or more beams of light corresponding to the majoritypolarization state to provide a first beam of light corresponding to themajority polarization state. Process 700 may proceed from 730 to 740.

At 740, process 700 may involve spatially stacking the split beam ofeach of the two or more beams of light corresponding to the minoritypolarization state to provide a second beam of light corresponding tothe minority polarization state. Process 700 may proceed from 730 to740.

At 750, process 700 may involve applying a majority polarization patternon the first beam of light. Process 700 may proceed from 750 to 760.

At 760, process 700 may involve applying a minority polarization patternon the second beam of light. Process 700 may proceed from 760 to 770.

At 770, process 700 may involve combining the patterned first and secondbeams of light to provide a single beam of light.

In some embodiments, the single beam of light may have an intensitygreater than an intensity of the two or more beams of light.

In some embodiments, in applying the majority polarization pattern onthe first beam of light, process 700 may involve applying the majoritypolarization pattern by an optically addressed light valve or a liquidcrystal display device corresponding to the majority polarization state.Additionally, in applying the minority polarization pattern on thesecond beam of light, process 700 may involve applying the minoritypolarization pattern by an optically addressed light valve or a liquidcrystal display device corresponding to the minority polarization state.

In some embodiments, in spatially stacking the split beam of each of thetwo or more beams of light corresponding to the majority polarizationstate to provide the first beam of light corresponding to the majoritypolarization state, process 700 may involve spatially stacking two ormore split beams of the two or more beams of light corresponding to themajority polarization state. Moreover, process 700 may involvehomogenizing the spatially stacked two or more split beams to providethe first beam of light.

In some embodiments, in spatially stacking the split beam of each of thetwo or more beams of light corresponding to the minority polarizationstate to provide the second beam of light corresponding to the minoritypolarization state, process 700 may involve spatially stacking two ormore split beams of the two or more beams of light corresponding to theminority polarization state. Furthermore, process 700 may involvehomogenizing the spatially stacked two or more split beams to providethe second beam of light.

In some embodiments, in splitting each of the two or more beams of lightinto two split beams each corresponding to the majority polarizationstate or the minority polarization state, respectively, process 700 mayinvolve spatially stacking the two or more beams of light prior to thesplitting. Additionally, process 700 may involve splitting each of thespatially combined two or more beams of light into the two split beamseach corresponding to the majority polarization state or the minoritypolarization state, respectively.

Many modifications and other embodiments of the invention will come tothe mind of one skilled in the art having the benefit of the teachingspresented in the foregoing descriptions and the associated drawings.Therefore, it is understood that the invention is not to be limited tothe specific embodiments disclosed, and that modifications andembodiments are intended to be included within the scope of the appendedclaims. It is also understood that other embodiments of this inventionmay be practiced in the absence of an element/step not specificallydisclosed herein.

What is claimed is:
 1. A method, comprising: applying a pattern on anaddressable patternable cathode unit; stimulating the cathode unit toemit an electron beam pattern; and positioning a patterned image in theelectron beam pattern to a desired position.
 2. The method of claim 1,wherein the applying of the pattern comprises applying a two-dimensionalpatterned image using a light projector
 3. The method of claim 1,further comprising: generating the patterned image with an electricallydriven imagery using an integrated emission array.
 4. The method ofclaim 2, further comprising: generating the patterned image by emittinglight from the light projector at a wavelength appropriate to stimulatea photoconductive layer.
 5. The method of claim 4, wherein thephotoconductive layer is stimulated by an optical field that enablesindividual emitters or one or more groups of emitters to produce anelectron beam.
 6. The method in claim 1, further comprising: focusingthe electron beam pattern directly to a powder bed in an electron beamsystem by using an ensemble of integrated focusing grids.
 7. The methodof claim 6, wherein the focusing of the electron beam pattern directlyto the powder bed comprises scanning the electron beam pattern in aone-dimensional (1D) or two-dimensional (2D) space across a print bed byusing an ensemble of scanning grids.
 8. The method of claim 7, whereinthe ensemble of scanning grids are either integrated into an fieldemission array or are constructed separately and assembled into asystem.
 9. The method of claim 7, wherein the scanning of the electronbeam pattern comprises optically activating the ensemble of scanninggrids through inclusion of photoconductors that are activated by opticalcontrol beams allowing for individual field emitters or groups thereinto be scanned up to three dimensions across the print bed as athree-dimensional (3D) scanning electron beam.
 10. The method of claim9, wherein the 3D scanning electron beam image is positioned below a topsurface of the powder bed to cause sub-surface melting.
 11. The methodof claim 2, wherein the stimulating of the cathode unit comprisesenergizing the cathode unit by an electrical power system when thetwo-dimensional patterned image is optically addressed.
 12. The methodof claim 6, wherein the focusing of the electron beam pattern comprisesfocusing the electron beam pattern using imaging coils of the imagerelay system.
 13. The method of claim 1, wherein the positioning of thepatterned image comprises positioning the patterned image using adeflection coil.
 14. The method of claim 13, wherein individual pixelsof the patterned image are scanned in up to three dimensions, inconjunction with global imaging positioning using a deflection coil. 15.The method of claim 1, wherein the positioning of the patterned image inthe electron beam pattern to the desired position comprises positioningthe patterned image in the electron beam pattern to a position on apowder bed of an additive manufacturing component.
 16. An apparatus,comprising: an optically addressable patterned cathode unit; a projectorconfigured to apply a pattern on the cathode unit; an electricity powersystem configured to stimulate the cathode unit to emit an electron beampattern; an image relay system configured to focus the electron beampattern using; and a deflection coil configured to position a patternedimage in the focused electron beam pattern to a desired position. 17.The apparatus of claim 16, wherein, in stimulating the cathode unit, theelectrical power system is configured to energize the cathode unit whenthe two-dimensional patterned image is optically addressed.
 18. Theapparatus of claim 16, wherein, in focusing the electron beam pattern,the image relay system is configured to focus the electron beam patternusing imaging coils of the image relay system.
 19. The apparatus ofclaim 16, further comprising: an additive manufacturing component havinga powder bed configured to hold one or more powdered materials thereon,wherein, in positioning the patterned image in the focused electron beampattern to the desired position, the deflection coil is configured toposition the patterned image to a position on the powder bed of theadditive manufacturing component.
 20. A method, comprising: emitting oneor more electron beams from a cathode unit array; forming a pattern withthe one or more electron beams; stimulating a via array to generate aspatial voltage pattern across a linear electro-optical layer in areflective light valve system; sending an unpatterned polarized opticalbeam into the linear electro-optical layer; transferring the spatialpattern within the linear electro-optical layer to a polarizationpattern in the optical beam
 21. The method of claim 20, wherein theoptical beam with a polarization pattern is passed through a polarizerto produce: a first beam with a first portion of the pattern, a secondbeam with the second, inverse portion of the pattern; and an imagingsystem is used to relay the image formed at the electro-optical layer toa powder bed, forming a portion of an additively manufactured part. 22.The method of claim 21, wherein the applying of the pattern comprisesapplying a two-dimensional (2D) patterned image using a projector. 23.The method of claim 22, wherein generating the 2D patterned image by anelectrically driven imagery using an integrated emission array.
 24. Themethod in claim 21, wherein the addressing of the structured via arraycomprises creating both positive and negative voltages by a secondaryemission grid to transmit positive and negative fields to the linearelectro-optic layer.
 25. The method of claim 24, wherein the positiveand negative fields allow for fringe field switching and in-planeswitching modes in the linear electro-optic layer comprising a liquidcrystal or similar materials.